Systems and methods for multicast admission control

ABSTRACT

Systems and methods for multicast admission control are provided. In one embodiment, a node comprises: a first interface configured to receive a multicast channel access request, from a subscriber interface, including an address for a channel; a memory including a subscriber profile and VLAN configuration data for the network; a processor that identifies a first VLAN corresponding to the address from the VLAN configuration data and determines whether the subscriber is authorized to receive the channel via the first VLAN based on access policy designated by the subscriber profile; wherein the processor further determines whether granting access to the channel violates admission control policy based on predefined bandwidth requirements and/or a stream count limit for the first VLAN; wherein when the subscriber interface is authorized to receive the channel and when granting access to the channel does not violate admission control policy, the processor routes the channel to the subscriber.

BACKGROUND

Media content distribution networks, such a cable television networks,provide multiple services to subscribers such as Internet, video contentand video on demand. Operators of these networks need to make sure thatthere is enough capacity available for each of these services, that thedelivery of these services do not overwhelm or impact each other, andthat the quality of service is preserved for each service. Typically, itis necessary to accurately account for how much capacity is needed todeliver each service and compare that capacity with designatedsubscriber limits to make sure no subscriber is able to place a demandon the network that exceeds what they are entitled to. The process ofregulating subscriber demands on the network is referred to as admissioncontrol.

One challenge associated with admission control for video services comesfrom the fact that different content will have different capacityrequirements. For example, given an available content channel lineupthat includes High Definition (HD) content, Standard Definition (SD)content, and audio content (e.g. a radio channel), the HD quality videowill consume a network capacity of 6 to 8 MB/sec, SD video will consume2.2 to 2.7 MB/sec, and a radio stream will typically consume 64 to 128kB/sec. In addition, overhead and management channels can occupymultiple low capacity multicast streams. These overhead channels are lowcapacity, but there are often several of them. To manage content for asubscriber entitled to 20 MB of video service (for example), and enforcethe 20 MB limitation, the network must account for the capacity of theservices being used by the subscriber.

For the reasons stated above and for other reasons stated below whichwill become apparent to those skilled in the art upon reading andunderstanding the specification, there is a need in the art for improvedsystems and methods for multicast admission control.

SUMMARY

The Embodiments of the present invention provide methods and systems formulticast admission control and will be understood by reading andstudying the following specification.

In one embodiment, a node for managing admission control of multicastcontent on a content distribution network comprises: a first interfaceconfigured to receive a multicast channel access request from at leastone subscriber interface, the multicast channel access request includinga multicast address for a channel stream; a memory including asubscriber profile for a subscriber associated with the at least onesubscriber interface and VLAN configuration data for the contentdistribution network; a processor coupled to the first interface and thememory; wherein the processor identifies a first VLAN corresponding tothe multicast address from the VLAN configuration data and determineswhether the at least one subscriber interface is authorized to receivethe channel stream via the first VLAN based on an access policydesignated by the subscriber profile; wherein the processor furtherdetermines whether granting access to the channel stream violates anadmission control policy based on one or both of a predefined bandwidthrequirement for the first VLAN and a stream count limit for the firstVLAN; wherein when the at least one subscriber interface is authorizedto receive the channel stream via the first VLAN and when grantingaccess to the channel stream does not violate the admission controlpolicy, the processor routes the channel stream to the at least onesubscriber interface.

DRAWINGS

Embodiments of the present invention can be more easily understood andfurther advantages and uses thereof more readily apparent, whenconsidered in view of the description of the preferred embodiments andthe following figures in which:

FIGS. 1A and 1B are block diagrams illustrating a multicast mediadelivery network of one embodiment of the present invention;

FIG. 2 is a diagram illustrating one embodiment of the presentinvention; and

FIG. 3 is a flow chart illustrating a method of one embodiment of thepresent invention.

In accordance with common practice, the various described features arenot drawn to scale but are drawn to emphasize features relevant to thepresent invention. Reference characters denote like elements throughoutfigures and text.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings that form a part hereof, and in which is shown byway of specific illustrative embodiments in which the invention may bepracticed. These embodiments are described in sufficient detail toenable those skilled in the art to practice the invention, and it is tobe understood that other embodiments may be utilized and that logical,mechanical and electrical changes may be made without departing from thescope of the present invention. The following detailed description is,therefore, not to be taken in a limiting sense.

FIG. 1A is a block diagram illustrating a multicast media deliverynetwork 100 of one embodiment of the present invention. Network 100comprises a middleware application 112 executing on a server 110 locatedat an operator's central office (CO) 105. Middleware application 112 islinked to one or more content sources 120 (via a satellite link, forexample). Network 100 further comprises a plurality of access nodes(shown at 140 and 150) coupled to server 110 via at least one multicastrouter 130. Although only access node 140 is described herein in detail,it is understood that access nodes 150 will operate under the sameprinciple of operation as described herein for access node 140.

Access node 140 is the immediate network device for providingsubscribers with access to content delivered by media delivery network100. That is, access node 140 is coupled via a single hop connection tothe subscriber's equipment, illustrated as subscriber interfaces 160 and162. Subscriber interfaces 160 and 162 comprise devices such as, but notlimited to, a set top box, a television installed cable television card,a personal computer, or other media presentation device. Subscriberinterfaces 160 and 162 function to provide a viewer with channel lineupinformation, the ability to request a viewer specified channel, anddeliver requested content provided by access node 140 to the viewer.Embodiments of the present invention provide systems and methods ofadmission control for regulating the content from media delivery network100 that is available via subscriber interfaces 160 and 162.

As would be appreciated by one of ordinary skill in the art uponstudying this specification, the greater the distance between subscriberinterfaces 160 and 162 and the network device that performs admissioncontrol for network 100, the greater the delay that is introduced whenaccepting or rejecting a subscriber's content requests. Accordingly,making admission control decisions at the access node 140 will providequicker responses to subscriber requests than if admission controldecisions were performed by middleware application 112. At the sametime, the operators of network 100 do not want to distribute too muchresponsibility down to the access node 140, which would tend to increasethe complexity and costs associated with designing, fabricating, andoperating access nodes. For example, the upstream middleware application112 typically handles requests for over 100,000 subscribers whereas theaccess node 140 handles a single subscriber. If a function that could beperformed by middleware application 112 is pushed down to the accessnode 140 level, that function would then have to be implemented at100,000 different locations (for this example). Further, the networkoperator has less control over ensuring the availability of resourcessuch a power at access node 140 installation locations than at centraloffice 105. As such, when functions are pushed down to the access node140 level, such functions need to be implemented as simply as possible,optimizing the processing capabilities and power resources available atthat level.

To address these considerations, embodiments of the present inventionemploy a scheme which places primary responsibility for admissionscontrol at the access node 140, but simplifies the information anddecision making structure necessary at access node 140. Morespecifically, embodiments of the present invention utilize virtual localarea network (VLAN) designations to simplify the designation of mediacontent types and specify network capacity requirements associated witheach media content type, and utilize policies that regulate subscriberaccess as a function of the VLAN designation. As illustrated in FIG. 1B,access node 140 further includes an interface 141 for communicating withsubscriber interfaces 160 and 162, and a processor 143 coupled to amemory 148 that comprises VLAN Configuration Data 142, Access PolicyData 144 and a Subscriber Profile 146, each of which are described ingreater detail herein.

Table 1, shown below, provides an example of the contents of VLANConfiguration Data 142 for one embodiment of the present invention.

TABLE 1 Multicast MVLAN Content Service Bandwidth Address Range ServiceVLAN 10 HD  8 Mbits 239.100.100.1- IPTV 239.100.100.200 VLAN 20 SD  3Mbits 240.100.88.1- IPTV 240.100.88.200 VLAN 30 Audio 64 Kbits239.100.66.1- Radio 239.100.99.200 VLAN 40 Management N/A 240.1.100.1-IPTV 240.1.100.200 VLAN 50 Data  6 Mbits 239.5.100.1- Data 239.5.100.200

As shown in Table 1, High Definition IPTV content is available in VLAN10 from addresses within multicast address range239.100.100.1-239.100.100.200, Standard Definition IPTV content isavailable in VLAN 20 from addresses within multicast address range240.100.88.1-240.100.88.200, Audio only content, such as internet radiochannels, is available in VLAN 30 from addresses within multicastaddress range 239.100.66.1-239.100.99.200, and so on. Note that it isnot necessary for VLAN Configuration Data 142 to specify any informationfor specific channels. When a viewer at subscriber interface 160requests access to address 239.100.100.50 (as an example), VLANConfiguration Data 142 tells access node 140 that the requested addressfalls in the multicast address range assigned to VLAN 10, and to accountfor 8 MB of capacity usage against the subscriber's maximum entitlement(if one exists). The access node does not need to know anything morespecific about the particular content being requested for the purpose ofkeeping track of capacity demand. As such, the network operator canalter its channel lineup within a VLAN without the need to push capacityinformation about each channel in that lineup to access node 140.Instead, the network operator only needs to ensure that channels arecorrectly placed into the multicast address range for the appropriateVLANs for their content type.

Once a VLAN associated with a subscriber's request is determined,information provided by access policy data 144 and subscriber profile146 is utilized by access node 140 to determine if access will begranted to the requesting subscriber.

Table 2 provides an example of a set of subscriber profiles (such asprovided by access policy data 144 and/or subscriber profile 146) forone embodiment of the present invention.

TABLE 2 Service Upstream Downstream Policy Level Direction BandwidthBandwidth Classifier P1 IPTV-Gold Down N/A 30 Mbit C1 P2 IPTV-SilverDown N/A 10 Mbit C2 P3 IPTV- Bi- 2 Mbit 20 Mbit C3 Video + directionalVideo on Demand

Each subscriber profile identifies a policy (designated, for example, asP1, P2, P3 . . . ) that defines a service level that a subscriber isentitled to receive and may be associated with programming packagesmarketed to subscribers by the network operator. Each policy defineswhether an authorized service requires only downstream capacity or,alternately, bidirectional capacity, and defines the subscriber'smaximum bandwidth entitlement under that policy for both upstream anddownstream capacity. For example, a subscriber having a programmingpackage governed by policy P1 is limited to a maximum downstreamcapacity usage of 30 MB. Another subscriber having a programming packagegoverned by policy P2 is limited to a maximum downstream capacity usageof 10 MB. A classifier definition is associated with each Policy is alsoshown in Table 2. As illustrated in Table 3, the classifier definitioncan provide information such as, but not limited to, the subscriber droppacket format and the network transport packet format for the level ofservice, which content sources (i.e., multicast VLANS) can be accessedby the level of service, and optionally a filter to limit the subscriberto a only a subset of the content available on the Multicast VLANs.

TABLE 3 Network transport Subscriber drop Multicast Classifier packetformat packet format VLAN Source Filter C1 N/A Untagged 10, 20, 30, 40Filter 1 C2 N/A VLAN = 10 50 Filter 2 C3 VLAN = 100, VLAN = 20 10, 40Filter 3 Pbit = 3

Table 4 provides another example of possible admission control policiesprovided by access policy data 144. In Table 4, admission controlpolicies are defined in terms of stream count limits and total bandwidthcapacity limits. When the operator is defining the stream count limitsthey can utilize logical operators (OR and AND) as part of the rules—asan example the subscriber can be entitled to 2 HD OR 2 SD streams or 2HD AND 2 SD streams. When stream count and bandwidth constraints areboth used the access node verifies a content request against bothpolicies before the content request is granted.

TABLE 4 Total Bandwidth Policy Stream Count Limits Capacity Limit P110-1 AND 20-3 AND 40-5 15 Mbit P2 10-2 OR 30-2 AND 40-5 N/A P3 10-2 OR30-2 AND 50-1 AND 40-5 16 Mbit

For the embodiment shown in FIG. 1, the access policy data 144 is pushedout to access node 140 (and each of access nodes 150) on network 100 bya central policy server 116. As shown in FIG. 1, Central policy server116 is implemented by server 110 at central office 105. In otherembodiments, central policy server 116 is implemented by a separateserver which may be located anywhere on network 100. Thus when a policyis changed, or policies are added or deleted, the network operator needonly provide the update to the policy server 116. The policy server 116will then provide access policy data updates to the appropriate accessnodes 140, 150. In alternate embodiments, the access policy data 144resident on access node 140 can be configured directly by the networkoperator on a node-by-node basis.

FIG. 2 is a sequence diagram depicting FIG. 1 in operation for oneembodiment of the present invention. In particular, FIG. 2 illustrates asequence where a subscriber interface places a request to an access nodeto receive media content.

The sequence begins at 210 where a subscriber powers up subscriberinterface 160. For the purposes of this example, it can be assumed thatsubscriber interface 160 is a set-to-box. Middleware application 112 haspreviously delivered to subscriber interface 160 a channel line-uplisting that provides the subscriber with a listing of channels andmaintains a multicast address for each channel. Next, at 212, thesubscriber interface 160 requests access to a channel stream. Becausethe subscriber interface has just been powered up, it will requestsaccess to the last previously viewed channel (“The Discovery Channel HD”for example). In one embodiment, subscriber interface 160 requestscontent from access node 140 using the Join command of the InternetGroup Management Protocol (IGMP) protocol. The IGMP protocol operatesprimarily using three primitives: the join request, the leave request,and the general query. For the join request, the subscriber interface160 provides the multicast address for the requested channel stream toaccess node 140.

At 214, the access node determines which VLAN includes the multicastaddress of the requested channel, using the VLAN configuration data.This also serves to confirm that the requested content is in factavailable via the content distribution network. Proceeding to 216,access node 140 determines whether the subscriber is authorized toreceive content from the identified VLAN, based on the access policydesignated by the subscriber's profile. In one embodiment, details ofthe access policy are stored in access policy data 144. That is, thesubscriber profile 146 specifies under which policy the subscriber isauthorized to receive content, and access policy data 144 specifies thepermitted VLANs the subscriber can access and any access limits for thatpolicy.

For example, assume that subscriber profile 146 indicates that thesubscriber is authorized under policy P1 and the join request fromsubscriber interface 160 is for address 239.100.100.50. Access node 140looks up the address in Multicast VLAN configuration data 142 anddetermines that the request is within VLAN 10. Since VLAN 10 is anauthorized content source under policy P1, the subscriber is authorizedto access content from that multicast stream.

When the subscriber is not authorized to receive the requested content,access node 140 routes an error stream (shown at 218 as “error stream‘A’”) back to the subscriber interface instead of the requested content.In one embodiment, when this occurs, instead of propagating a requestupstream for the requested content, access node 140 instead sends a joinrequest to the upstream multicast router (shown at 232) for the desirederror stream. Error stream “A” may provide a detailed error messageexplaining that the requested channel is not available under the user'ssubscription, or alternatively may simply indicate that access to thecontent is denied. The subscriber interface would then display thaterror stream content (shown at 220) rather than the requested content.

When the subscriber is not authorized to receive the requested content,the sequence proceeds to 222 where access node 140 determines whethergranting the request violates the admission control policy. That is,even when the subscriber is authorized to access the requested content,access node 140 will decline access if granting access will violate theadmission control policy. For this example, policy P1 indicates that thesubscriber is authorized to receive a single VLAN 10 (HD) channels andup to three VLAN 20 (SD) channels, not to exceed a downstream bandwidthlimit of 15 MB/sec (See, Table 4). Since the subscriber is currentlyreceiving no other multicast streams, the join request for a first VLAN10 channel will not violate the admission control policy's stream countlimit. Further, the bandwidth allocation of 8 Mbits for a first VLAN 10channel will not violate the admission control policy's bandwidthcapacity limit of 15 MB/sec.

Thus, when the request does not violate admission control policy, thesequence proceeds to 228 where access node 140 routes the requestedchannel stream for the requested address to subscriber interface 160. Ifaccess node 140 is not already receiving the requested content, theaccess node will propagate the join request up to the multicast router(shown at 234) and configure a link to the subscriber interface 160 sothat the subscriber will display the content (shown at 230) as soon asaccess node 140 starts receiving the content. If the access node isalready receiving content from the requested multicast stream, thenpropagating the join request up the multicast router is unnecessary.

To continue this example, next assume that a viewer using subscriberinterface 162 sends a join request to access node 140 for another HDchannel at multicast address 239.100.100.90. As before, access node 140will proceed to 214 and 216 to confirm that the requested content isavailable and determine the VLAN for the requested content. Since239.100.100.90 is within the address range for VLAN 10, the subscriberis authorized to access the content of that HD channel. As before, theaccess node will proceed to 222 to determine if granting the subscriberto access the content will violate the admission control policy. Thistime, because the subscriber is already receiving a VLAN 10 multicaststream via subscriber interface 160, the join request from subscriberinterface 162 will violate the admission control policy's VLAN streamcount limit of one VLAN 10 channel.

Accordingly, when the request will violate the admission control policy,the sequence proceeds to 224 where access node 140 will route errorsteam “B” to subscriber interface 162. Error stream “B” may provide adetailed message explaining the subscriber has exceeded theirsubscription limits, or a simple message such as “access denied.”

For both blocks 218 and 224, instead of providing content from therequested address, access node 140 is configured to deliver a multicaststream that contains a simple error message. In one embodiment, accessnode 140 requests an error stream from server 110 which provides errorstream content (such as shown at 114). The error streams may berequested via standard IGMP protocol “join” messages as mentioned above.Access node 140 then delivers the error stream to the subscriberinterface as if it was the requested content. In one embodiment, accessnode 140 modifies the address within error streams so that it appears tothe subscriber interface as if an error stream was being delivered fromthe requested multicast address. In one embodiment, the error streamwill deliver a simple text message against a static background (such asa blue background, for example) notifying the user at the secondset-top-box that the requested channel is not available and the reasonswhy. The error stream could further provide the user with a phone numberor internet address with instructions on how to increase theirsubscription level to increase their subscription limits. Because thecontent of the error stream is not complex, the network capacityconsumed to deliver the error stream is not significant.

If instead of requesting another HD channel, the user at subscriber unit162 requested an SD channel at multicast address 240.100.88.25, accessnode 140 will proceed to 214 and 216 to correlate the requestedmulticast address against Multicast VLAN configuration data 142. Since239.100.88.25 is within the address range for VLAN 20, then under policyP1 the subscriber is authorized to access the content of that SDchannel. As before, the access node will again proceed to 222 todetermine if granting access the content at this time will violate theadmission control policy. In this case, although the subscriber iscurrently already receiving a VLAN 10 multicast stream at subscriberinterface 160, the join request for a VLAN 20 channel will not violatethe admission control policy's VLAN stream count limit because thesubscriber under policy P1 is entitle to access up to three VLAN 20channels in addition to the one VLAN 10 channel. Further, the requestfor the SD channel will not violate the admission control policy'sbandwidth capacity limit because the aggregate capacity demand of 11MB/sec (one VLAN 10 stream at 8 MB/sec plus one VLAN 20 stream at 3MB/sec) does not exceed the P1's capacity limit of 15 MB/sec.

Because this request does not violate the admission control policy, thesequence proceeds to 228 with access node 140 routing the requestedchannel stream from the requested address to the requesting subscriberinterface. If access node 140 is not already receiving the requestedcontent, it will propagate the join request up to the multicast router(as shown at 234) and configure a link to subscriber interface 162 sothat the user will receive the requested SD content as soon as theaccess node 140 starts receiving the content.

As illustrated by the examples above, for admission control purposes, anaccess node does not require specific modulation or bandwidth detailsfor a channel stream requested by a subscriber. It simply needs to knowwhich VLAN the multicast address for that stream falls within. If thenetwork operator shuffles its channel lineup, no modification at theaccess node is necessary for admission control purposes becauseadmission control decisions are made based on VLAN designations.Authorization to access requested content can be verified by confirmingthat the policy designated by the subscriber's profile includes the VLANfor the multicast address of the requested content. Stream limits areenforced by simply keeping track of how many different streams are beingdelivered to a subscriber from each VLAN. Bandwidth capacity limits areenforced by keeping an aggregate total of the capacity requirements foreach VLAN based on how many different streams are being delivered fromeach VLAN. Similarly, if a particular content provider alters the CODECused to encode a multicast stream they provide, modification at theaccess node is not necessary for admission control purposes as long asthe multicast stream remains in an appropriate VLAN for its content type(HD/SD/Audio, etc.) and maximum capacity requirements. Further becausethe network device that performs admission control is the access node(which is only one network hop from the subscriber interface) the amountof delay introduced when accepting or rejecting a subscriber's contentrequests is less than if the admission decisions were made further upthe network, such as at the multicast router or middleware application.

FIG. 3 is a flow chart illustrating a method of one embodiment of thepresent invention performed at a node of a media content distributionnetwork. In one embodiment, said node of the media content distributionnetwork is an access node coupled to one or more subscriber interfaces.In other embodiments, said node of the media content distributionnetwork is a node other than an access node. In one embodiment, themethod of FIG. 3 is performed using the network structure describe withrespect to FIGS. 1 and 2. In other embodiments, other network structuresare used. In one embodiment, the method of FIG. 3 is embodied bycomputer executable instructions stored on a computer readable mediumdevice. In another embodiment, the method is embodied by a processor atthe node executing instruction code that implements the method.

The method begins as 310 with receiving a request for a channel streamfrom a subscriber interface. In one embodiment, the request includes anetwork address which provides the channel stream. The method proceedsto 320 with identifying a VLAN that includes the channel stream based onVLAN configuration data for the content distribution network. In oneembodiment, the node identifies which VLAN includes the channel streamby accessing a table of VLAN configuration data. The method proceeds to330 with determining when access to the channel stream is authorizedover the VLAN based on an access policy designated by a subscriberprofile. In one embodiment, determining if access to the channel streamis authorized comprises accessing a table of access policy data todetermine if the access policy permits access to the VLAN that includesthe requested channel stream.

When access to the VLAN is not authorized (checked at 335), the methodproceeds to 340 with providing an error stream to the subscriber inplace of the channel stream. In one embodiment, if the node is notalready receiving the error stream, it will propagate a join request upto the multicast router and configure a link to the subscriber interfaceso that the user will receive the error stream in place of the requestedcontent as soon as the node starts receiving the error stream. In oneembodiment, the node replaces the network address in the error streamwith the network address for the requested channel stream so that itappears to the subscriber interface as if it is receiving the content itrequested.

When access is authorized (checked at 335), the method proceeds to 350with determining whether granting access to the channel stream violatesan admission control policy based on one or both of a predefinedbandwidth requirement for the VLAN and a stream count limit for theVLAN.

In one embodiment, granting access to the channel stream violates theadmission control policy when granting access will cause a stream-countto exceed a stream count limit for the VLAN. That is, the admissioncontrol policy is violated when granting access to the channel streamwould cause a stream count of channel streams received via the VLAN toexceed the stream count limit. In one embodiment, the stream count limitfor the VLAN is defined by the admission control policy. Alternatively,the admission control policy may be violated when adding the predefinedbandwidth requirement for the first VLAN to a current aggregatebandwidth usage would exceed a total bandwidth capacity limit defined bythe admission control policy. The current aggregate bandwidth can bedetermined, for example, by multiplying the stream-count for each VLANbeing delivered to the subscriber by the predetermined bandwidthcapacity requirement associated with each respective VLAN.

In one embodiment, when granting access to the channel stream violatesthe admission control policy (checked at 355), the method proceeds to360 with providing an error stream to the subscriber in place of thechannel stream. This error stream is provided to the subscriber in thesame way as the error stream described above for block 340. In alternateembodiments, the error stream provided at 360 may be the same errorstream that would be provided at block 340, or may be a different errorstream.

When access to the channel stream does not violate the admission controlpolicy (checked at 355) the method proceeds to 370 with routing thechannel stream from an upstream network device to the at least onesubscriber interface. If the node is not already receiving the requestedcontent, it will propagate the join request up to the multicast routerand configure a link to the subscriber interface so that the user willreceive the requested content as soon as the node starts receiving thechannel stream.

Several means are available to implement the systems and methodsdiscussed in this specification. These means include, but are notlimited to, digital computer systems, embedded processors,microprocessors, general purpose computers, programmable controllers andfield programmable gate arrays (FPGAs) or application-specificintegrated circuits (ASICs). Therefore one or more embodiments of thepresent invention are program instructions resident on computer readablemedia which when implemented by such means enable them to implementembodiments of the present invention. Computer readable media for thememory and storage devices describe above include any form of a physicalcomputer memory storage device. Examples of such a physical computermemory device include, but is not limited to, punch cards, firmware,magnetic disks or tapes, optical data storage system, flash read onlymemory (ROM), non-volatile ROM, programmable ROM (PROM),erasable-programmable ROM (E-PROM), random access memory (RAM), or anyother form of permanent, semi-permanent, or temporary memory storagesystem or device. Program instructions include, but are not limited tocomputer-executable instructions executed by computer system processorsand hardware description languages such as Very High Speed IntegratedCircuit (VHSIC) Hardware Description Language (VHDL).

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement, which is calculated to achieve the same purpose,may be substituted for the specific embodiment shown. This applicationis intended to cover any adaptations or variations of the presentinvention. Therefore, it is manifestly intended that this invention belimited only by the claims and the equivalents thereof.

What is claimed is:
 1. A node for managing admission control ofmulticast content on a content distribution network, the nodecomprising: a first interface configured to receive a multicast channelaccess request from at least one subscriber interface, the multicastchannel access request including a multicast address for a channelstream; a memory including a subscriber profile for a subscriberassociated with the at least one subscriber interface and Virtual LocalArea Network (VLAN) configuration data for the content distributionnetwork; a processor coupled to the first interface and the memory;wherein the processor identifies a first VLAN corresponding to themulticast address from the VLAN configuration data and determineswhether the at least one subscriber interface is authorized to receivethe channel stream via the first VLAN based on an access policydesignated by the subscriber profile; wherein the processor furtherdetermines whether granting access to the channel stream violates anadmission control policy based on one or both of a predefined bandwidthrequirement for the first VLAN and a stream count limit for the firstVLAN; wherein when the at least one subscriber interface is authorizedto receive the channel stream via the first VLAN and when grantingaccess to the channel stream does not violate the admission controlpolicy, the processor routes the channel stream to the at least onesubscriber interface.
 2. The node of claim 1, wherein the node comprisesan access node coupled by a single hop connection to the at least onesubscriber interface via the first interface.
 3. The node of claim 1,wherein the VLAN configuration data segregates multicast addresses forchannel streams providing a first content type into the first VLAN,multicast addresses for channel streams providing a second content typeinto a second VLAN, and multicast addresses for channel streamsproviding a third content type content into a third VLAN.
 4. The node ofclaim 3, wherein the VLAN configuration data segregates multicastaddresses for one or more channel streams providing a high definitioncontent into the first VLAN, and multicast addresses for one or morechannel streams providing a standard definition content into the secondVLAN.
 5. The node of claim 1, wherein the at least one subscriberinterface is not authorized to receive the channel stream via the firstVLAN when the access policy does not designate the first VLAN as anauthorized VLAN.
 6. The node of claim 1, wherein the access policyfurther comprises a filter that limits access to only a subset ofcontent available via the first VLAN.
 7. The node of claim 1, whereinthe at least one subscriber interface is authorized to receive thechannel stream via the first VLAN when the access policy designates thefirst VLAN as an authorized VLAN.
 8. The node of claim 1, wherein theadmission control policy is violated when adding the predefinedbandwidth requirement for the first VLAN to a current aggregatebandwidth usage would exceed a total bandwidth capacity limit defined bythe admission control policy.
 9. The node of claim 1 wherein theadmission control policy is violated when granting access to the channelstream would cause a stream count of channel streams received via thefirst VLAN to exceed the stream count limit for the first VLAN, whereinthe stream count limit for the first VLAN is defined by the admissioncontrol policy.
 10. The node of claim 1, wherein when either the atleast one subscriber interface is not authorized to receive the channelstream, or granting access to the channel stream would violate theadmission control policy, the processor routes an error stream to the atleast one subscriber interface in place of the channel stream.
 11. Amethod for managing admission control of multicast content on a contentdistribution network, the method comprising: receiving a request for achannel stream from a subscriber interface; identifying a Virtual LocalArea Network (VLAN) that includes the channel stream based on VLANconfiguration data for the content distribution network; determiningwhen access to the channel stream is authorized over the VLAN based onan access policy designated by a subscriber profile; determining whethergranting access to the channel stream violates an admission controlpolicy based on one or both of a predefined bandwidth requirement forthe VLAN and a stream count limit for the VLAN; when access to thechannel stream is authorized over the VLAN and when granting access tothe channel stream does not violate the admission control policy,routing the channel stream from an upstream network device to the atleast one subscriber interface; and when either access to the channelstream is authorized over the VLAN is not authorized, or granting accessto the channel stream violates the admission control policy, routing anerror stream to the at least one subscriber interface in place of thechannel stream.
 12. The method of claim 11, where receiving a requestfor the channel stream from a subscriber interface further comprisesreceiving a IGMP protocol Join request that includes a network addressfor the channel stream.
 13. The method of claim 11, wherein identifyinga VLAN that includes the channel stream based on VLAN configuration datafor the content distribution network comprises: accessing a table ofaccess policy data to determine if a policy permits access to the VLAN.14. he method of claim 11, wherein the admission control policy isviolated when adding the predefined bandwidth requirement for the VLANto a current aggregate bandwidth usage would exceed a total bandwidthcapacity limit defined by the admission control policy.
 15. The methodof claim 11, wherein the admission control policy is violated whengranting access to the channel stream would cause a stream count ofchannel streams received via the VLAN to exceed the stream count limitfor the VLAN, wherein the stream count limit for the VLAN is defined bythe admission control policy.
 16. The method of claim 11, wherein themethod is performed at an access node coupled by a single hop connectionto the subscriber interface.
 17. The method of claim 11, wherein theVLAN configuration data segregates multicast addresses for channelstreams providing a first content type into the first VLAN, multicastaddresses for channel streams providing a second content type into asecond VLAN, and multicast addresses for channel streams providing athird content type content into a third VLAN.
 18. The method of claim11, wherein the access policy further comprises a filter that limitsaccess to only a subset of content available via the VLAN.
 19. A nodefor managing admission control of multicast content on a contentdistribution network, the node comprising: a first interface configuredto receive a multicast channel access request from at least onesubscriber interface, the multicast channel access request including amulticast address for a channel stream; a memory including a subscriberprofile for a subscriber associated with the at least one subscriberinterface and Virtual Local Area Network (VLAN) configuration data forthe content distribution network; a processor coupled to the firstinterface and the memory, the processor configured to execute computerexecutable instructions for a method for managing admission control, themethod comprising: receiving the multicast channel access request fromthe first interface; identifying a VLAN that includes the multicastaddress based on the VLAN configuration data; determining when access tothe channel stream is authorized over the VLAN based on an access policydesignated by the subscriber profile; determining whether grantingaccess to the channel stream violates an admission control policy basedon one or both of a predefined bandwidth requirement for the VLAN and astream count limit for the VLAN; when access to the channel stream isauthorized over the VLAN and when granting access to the channel streamdoes not violate the admission control policy, routing the channelstream from an upstream network device to the at least one subscriberinterface; and when either access to the channel stream is authorizedover the VLAN is not authorized, or granting access to the channelstream violates the admission control policy, routing an error stream tothe at least one subscriber interface in place of the channel stream.20. The node of claim 19, wherein the admission control policy isviolated when adding the predefined bandwidth requirement for the VLANto a current aggregate bandwidth usage would exceed a total bandwidthcapacity limit defined by the admission control policy; and wherein theadmission control policy is violated when granting access to the channelstream would cause a stream count of channel streams received via theVLAN to exceed the stream count limit for the VLAN, wherein the streamcount limit for the VLAN is defined by the admission control policy.